Such a sensing device may be an in-vivo sensing device, such as a capsule used, for example, for sensing of passages or cavities within a body, and for collecting data (e.g., image data, pH data, temperature information, pressure information), as known in the art. Such sensing devices are generally used in conjunction with other equipment that may include, inter alia, various endoscopic imaging systems and equipment for performing imaging in various internal body cavities. Some such sensing devices transmit the collected data to an external receiving unit.
The in-vivo sensing device may include, for example, an imaging system for obtaining images from inside a body cavity or lumen, such as the gastrointestinal (GI) tract. The imaging system may include, for example, an illumination unit, such as a set of light emitting diodes (LEDs), or other suitable light sources. The device may include an imaging sensor and an optical system, which focuses the images onto the imaging sensor. A transmitter and antenna may be included for transmitting the images signals. Alternatively, a transceiver may be included so that the in-vivo sensing device may receive signals from an external transmitter. An external receiver/recorder, for example worn by the patient, may record transmitted image data and store image and other data. The recorded data may then be downloaded from the receiver/recorder to a computer or workstation for display and analysis.
The transmitter/transceiver and illumination unit of the in-vivo sensing device may be powered by a battery installed therein during production. The production process involves various stages during which the battery may be intentionally or accidentally activated and consequently use some of its power. After production, the device may be stored for a period of time and then shipped to a customer over another period of time. During these periods of time, the battery may also possibly be accidentally activated and therefore use some of its power. The total time for which the battery was in use prior to the device reaching the customer is a measure of the remaining battery life time.
Sensing of passages or cavities within a body may take several hours. Clearly, it is undesirable to use an in-vivo sensing device having a battery that is inoperative, or that may become inoperative before the in-vivo sensing device has completed imaging the required length of passages or cavities within the body that are under inspection. In general, components of the in-vivo sensing device have specified operating voltage ranges. Situations may arise in which the in-vivo sensing device's battery may become defective before use by the patient, or its voltage may not be constant over a required period of time. Therefore, if the voltage of the battery was to fall below a certain critical voltage, some of the components may not function correctly, if at all.
The in-vivo sensing device may be a closed and sealed unit such as an autonomous swallowable capsule in which the battery was installed during production. Therefore, there is a need for a non-invasive method of checking the status of the battery, prior to use.